Vertical reciprocating pump having easily installed piston with flap valves

ABSTRACT

A vertically reciprocating pump is described, characterized by a piston which has a support including a hub extending downwards and supporting reinforcement legs, the hub having a rod to which it is translatably coupled passing therethrough, and by a valve overlying the support, which seals the piston under the weight of the column of liquid above it or allows the passage of liquid when the piston moves down the water column in the drainage pipe.

The present invention relates to a vertical reciprocating pump forraising fluids which are present in the ground.

A vertical reciprocating pump of this type is already known, inparticular as described in document OAPI 06 221 of Mar. 23, 1979. Pumpsof this type are designed to pump fluids which are present in theground, such as underground waters, petroleum etc.

The known vertical reciprocating pumps, which are designed to pumpwater, are operated manually. According to the depth of the fluid tablethey consist either of a rod or a vertical set of rods which support oneor a plurality of flap-valve pistons.

The known pistons generally consist of a cylinder of a specific length,which is provided on its periphery along one of its edges, and inparticular the upper edge, with a gasket which slides in the raisingtube.

This part of the cylinder is engaged in a sliding manner on a body,which for example consists of ribs and ends at its base in a flap valve.When the cylinder of the piston descends on the flap valve, the pistonis sealed. In the opposite case the fluid can pass through the piston.These two different positions between the cylinder and the flap valvecorrespond respectively to the movement of descent of the piston in thewater column contained in the cylinder of the pump body or raising tube,and to the movement of raising of the fluid column above the piston.

A multiple piston pumping device is also known (FR-88 09 575) in whichthe piston consists of a cylinder, the base of which has a so-calledalveolar structure. This cylinder is fitted onto the rod which controlsthe reciprocating motion. Above the alveolar base there is provided alifting flap valve which is maintained supported against the alveolarstructure by a tubular component. This tubular component passes throughthe interior of the cylinder and is supported against a stop which isintegral with the rod. Below the piston, i.e. below the alveolar base ofthe cylinder, a nut and counternut are provided to lock the assembly.

The cylinders of the known pistons have the disadvantage that they rubsubstantially on the inner surface of the raising column, and thisfriction increases when the raising tube sustains deformations as aresult of movements of the ground, since the piston is then forced tofollow this deformed path.

The gasket along the upper edge of the cylinder, which is appliedagainst the inner wall of the raising tube or the cylinder, itselfincreases this friction as a result of the pressure exerted by the fluidcolumn against the gasket and the cylinder.

The fluids which are pumped are often loaded, and eventually particlesare deposited on the seats of the flap valves of the piston. The pistonsthus lose their sealing, which decreases the flow of fluid pumped.Consequently the pistons must be replaced frequently, which increasesthe operating cost of the pump.

Since the flap valve is a wear part, it becomes worn and may need to bereplaced. In this case, the piston assembly must be dismantled in orderto access the flap valve, remove the flap valve to be changed, and putinto place the new flap valve. For this purpose it is necessary toremove the piston completely from the rod in order to be able to fit thenew flap valve.

This constitutes a relatively lengthy operation for replacement of avery simple part.

In addition, since the flap valve is located in the cylinder, when thepump is stopped the solid particles in suspension in the water which arecontinued in the piston are gradually deposited on the base. Since thepiston is not perfectly sealed, the water leaks out and carries with itthe solid particles in suspension which can be deposited between theedge of the diaphragm and the inner wall of the piston, during theinterval necessary in order to allow the flap valve to be raised withoutrubbing against the piston.

This situation is disadvantageous for pistons which are not immersed; iffor any reason the pump is stopped for a given time, i.e. for a fewhours or a few days, the solid particles then block the valve, andexperience has shown that in this case it is necessary to remove all thepistons from the water in order to dismantle them and release thediaphragms which are thus stuck.

This constitutes substantial work, and therefore a serious andinevitable disadvantage, since the pump is necessarily stopped from timeto time, even if only in the case of pumps which are operated manuallyor by a electric motor which is powered by solar batteries, without abuffer battery with a sufficient capacity for continuous operation.

The object of the present invention is to eliminate these disadvantagesby creating a reliable reciprocating pump with a simple structure, whichmakes it possible to pump fluids efficiently even from very deep fluidtables, and has a very regular flow rate even after a prolonged periodof use, and which, when necessary, can be maintained or replaced simply,or which prevents the flap valve of the piston or pistons which is/areabove the level of the water when the pump is stopped from being blockedby any particles in suspension in the water.

For this purpose, the invention relates to a vertical reciprocating pumpwhich corresponds to the above-described type.

The pistons are easily fitted on/removed from the rod or the assembly ofcomponents which constitute a set of rods of a pump for a substantialdepth.

The simplicity of production, associated with the small number of simpleparts which constitute a piston, permit assembly and above allinstallation of the pistons by unqualified workers, in installationconditions which are often rudimentary. The same applies to maintenanceinterventions.

Additionally, the structure of the piston prevents virtually alldepositing of solid particles and any blockage of the flap valve of thepiston or of the piston itself in its tube, since the piston is rinsedin operation and at the end of a pumping stage.

The specific shape of the piston has the advantage that it keeps to aminimum the contact with the inner suface of the raising tube.

In the simplest case the flap valve consists of a raisable diaphragmwhich rests on the support in order to support the water column, inaccordance with a feature which is advantageous for operation.

The diaphragm which forms the flap valve is cut at its outer edge as faras the aperture which is used for passage of the rod, such as to be ableto engage the diaphragm on the rod without having to thread it onto thelatter.

The diaphragm which is in the form of a split disc is very easilypositioned above the support, simply by unscrewing one of the two nutswhich maintain the support. This operation is carried out very quickly,and it is not at all necessary to remove the support of the rod, i.e. tocarry out problematic unscrewing operations.

The diaphragm can also consist of a plurality of segments whichpartially overlap. An embodiment of this type has the advantage ofsimplicity of installation and removal; it constitutes a flexible shapewhich allows the different segments to be raised partially or relativeto one another.

According to the conditions of use and operation of the pump, the pistonhas dimensions which are more or less close to the inner cross-sectionof the raising tube.

In order to make the pump function lightly and reduce the power requiredto make it operate, greater play is left than if the pump were operatedby a motor supplied by mains electrical energy, rather than by arelatively limited energy source.

Since in addition there is at the most only peripheral linear contactbetween the piston and the inner surface of the tube, even when theraising tube is deformed as a result of movements of the ground, thisvirtually does not impede at all the reciprocating motion of the piston,and in particular does not increase the friction forces between thepiston and the inner surface of the tube.

In the case of a pump used for a very deep water table, a flap valve inthe form of a diaphragm would not resist the water column, and in thiscase it consists of a rigid material, and more specifically the supportcomprises legs in the form of vertical triangles which are attached byone of their sides to the upper and auxiliary hub, and are joined aroundthe entire height of the support in order to form at the top part of thelatter branches for support and attachment of the flap valve.

The flap valve consists of segments of a disc which are each connectedby one of the radial sides to the upper radial part of a leg, and theother radial side of the flap valve is supported in the sealingposition, on the upper radial part of the following leg.

This embodiment has the advantage that it permits particularly efficientpumping of a very high water column without detracting from the ease ofdescent or strength of the piston.

In addition, a film of fluid is formed between the wall of the tube andthe piston or pistons, by this means virtually reducing the friction tozero, particularly since there is no gasket between the piston and thewall which would scrape away this fluid film.

The present invention is described hereinafter in greater detail bymeans of the attached drawings in which:

FIG. 1 is a schematic vertical cross-section of a vertical reciprocatingpump;

FIG. 2 is a partial schematic vertical cross-section of a pistondescending its rod;

FIG. 3 is a schematic vertical cross-section of the piston ascending therod;

FIG. 4 is an axial cross-sectional view of the piston support accordingto line IV--IV in FIG. 5;

FIG. 5 is a view from above of the piston support;

FIG. 6 is an exploded view of the piston;

FIG. 7 is a perspective view of another embodiment of a piston;

FIG. 8 is a side view of a support shell according to another embodimentof the invention;

FIG. 9 is a view from above of two support parts in the fittingposition;

FIG. 10 is a partial cross-section according to IX, showing the fullsupport assembled on a rod 7;

FIG. 11 is a perspective view of another embodiment and method ofassembly of a piston, this view being limited to the upper part of thesupport;

FIG. 12 is a partial cross-sectional view of a piston which is providedwith a skirt;

FIGS. 13A-15B are different embodiments of a piston support; and

FIG. 16 is a complete piston which is provided with a support accordingto one of the preceding embodiments.

According to FIG. 1, the vertical reciprocating pump according to theinvention consists of a base 1 which is supported on the ground 2. Avertical well 3 is integral with the base 1; it comprises a fluid outletspout 4 which discharges into a tank 5. This well tube 3 is prolonged atits lower end by a raising tube 6, including upper end 6a and lower end6b. This tube 6 accomodates a control rod 7 which is provided with oneor a plurality of pistons 8 which are described hereinafter. The lowerend 66 of the raising tube 6 is provided with a base flap valve 9.

The rod 7, which can also be a set of rods, i.e. an assembly of rodswhich are attached one after another, according to the depth of thewater table 99 from which pumping is being carried out, is controlled inreciprocating motion by a mechanism 10 which is shown only veryschematically. This mechanism 10 is supported by a frame 11. Themechanism 10 can be operated either manually, or by an animal, or by athermal or electric motor, and in the latter case an autonomous electricsupply unit can be used, for example solar-powered batteries.

The reciprocating vertical motion of the rod 7 and of the pistons 8firstly raises the fluid column which is supported on the pistons 8, anddischarges a specific quantity of fluid into the tank 5; the rod 7 thenlowers the pistons 8 inside the fluid column which is contained in theraising tube 6 and is retained by the base flap valve 9. When they reachthe lower end of travel, the pistons 8 are raised by the rod 7, and thusraise the fluid column above each piston. At the same time, the pistonabove the base flap valve 9 creates a depression above the latter. Thisdepression draws in fluid through the base flap valve 9 into the tube 6.The cycle continues thus.

FIGS. 2 and 3 show the structure of a first embodiment of a piston 8,i.e. firstly in FIG. 2 the position of descent of a piston 8 which isdriven by its rod 7, and then raising of the piston in FIG. 3.

In these figures the same reference numerals as in FIG. 1 are used todesignate the same components.

FIG. 2 is a partial axial cross-section of the raising tube 6, showingthe rod 7 or set of rods, consisting of a rod part 71 which is connectedto a rod part 72 by means of a threaded sleeve 74; the lower end 73 ofthe rod 71 is threaded beyond the extent which is necessary simply forscrewing the sleeve 74 in order to accomodate the piston 8. This piston8, which is attached between a lower nut 12 and an upper nut 13,consists of a support in the form of a disc which comprises an outerring 81 which is connected by radii 82 to an upper hub 83, through whichthere passes the rod 71 (or its threaded part 73), and it comprises alower hub 84 through which the rod 71 also passes; this lower hub 84holds the support by means of legs 85 which are connected to the ring81.

Above the support, the piston 8 has a flap valve, which in this caseconsists of a flexible diaphragm 87.

The radial form of the support, both at the legs 85 and at the radii 82,permits passage of the (raised) fluid in the direction of the arrows A,B, when the piston descends in the fluid column in the raising tube 6,as shown by the arrow C.

This descent of the piston 8 raises the diaphragm 87.

FIG. 3 shows the movement of raising the rod 7 (or rod components 71, 72in the case of a set of rods), which is identical to that in FIG. 2,according to raising movement which is indicated by the arrow D.

During this raising movement, the fluid column holds the flap valve 87against the support, and in particular the upper part of the support ofthe piston 8, i.e. the ring 81, the radii 82 and the upper hub 83, thusclosing the piston 8 in a sealed manner; this permits raising of thefluid column.

It should be noted that as already stated, the piston 8 is locked on therod 7 by the nuts 12, 13 which also retain the flap valve 87.

During the raising movement, the legs 85 transmit some of the forceapplied to the outer part of the support, towards the lower hub 84.

According to FIGS. 2 and 3, the outer ring 81 of the support has abeveled or rounded edge, thus reducing to a minimum the contact betweenthe piston 8 and the inner surface of the raising tube 6. This linearcontact describes a circle, lies in a plane P₁ -P₁, which plan P₁ -P₁includes a plurality of contact points 79 between piston 8 and raisingtube 6 and does not follow a cylindrical surface, which permitsabsorption of all the deviations or differences of alignment, forexample in curvature, between the rod 7 and the raising tube 6, thusreducing to a minimum the friction forces which oppose the raisingmovements.

In addition, the flap valve 87 is raised flexibly from the support 81,82, 83, and allows the fluid to rinse the support, thus preventing anydepositing of solid particles which would detract from sealing of thepiston for the raising movement.

Even if particles in suspension are deposited near the gap between theedge of the ring 81 and the inner surface of the raising tube 6 during aprolonged stoppage of the pump, when the raising or lowering movement isresumed the adhesion of the particles will be eliminated, since movementis transmitted directly by the rod or set of rods 7, 71, 72 to thepiston 8.

The cross-sections of the raising tube 6 and of the piston 8 arecircular, although this shape is not restrictive, and does not exclude apolygonal shape such as a hexagon or square etc.

FIGS. 4, 5, 6 show in greater detail the structure of a piston asdescribed above. FIG. 4 shows in cross-section the support with itsouter ring 81, a cross-section of a branch 82, the flange of the upperhub 83, one of legs in cross-section and another of legs 85 not incross-section, the intermediate rings 86 and the flange of the lower hub84. Half the diaphragm 87 is shown in cross-section in FIG. 4 and in topelevational view in FIG. 5. The other half of diaphragm 87 is not shownin FIGS. 4 and 5.

FIG. 5, which is a top elevational view of the apparatus illustrated inFIG. 4, shows half the diaphragm 87 and the different parts of thesupport, in particular the radii 82, the rings 81, 86 and the upper hub83 having between one another the gaps for passage of the fluid to bepumped.

The exploded view in FIG. 6 shows these different parts, i.e. the flapvalve in the form of a diaphragm 87, the support, and its componentparts 81, 82, 83, 84, 85, 86.

The piston support is a part which is produced for example in a singlepiece, for example from molded plastics material. The flap valve 87 ispreferably made of a flexible material such as synthetic rubber or aplastics material.

The dimensions of the flap valve are such that it covers the aperturesof the support and reaches close to the inner surface of the raisingtube, with a gap which is at least sufficient to leave a film of fluidalong the wall of the tube.

Although the flap valve 87 can be a part in the form of a disc whichfits onto the rod 7, according to FIG. 6 it is advantageously split,i.e. the disc which forms the flap valve 87 is cut along a line 88. Thiscutting line can be the joining line of the two edges of cutting of thedisc. This cutting line 88 extends from the outer edge 89 to theaperture 90 in the middle of the flap valve 87 which accommodates therod 71 (7).

The edges of the cutting line 88 can also overlap as shown by the brokenline 91. This line is in fact the edge of a part of the disc which isdisposed beneath the upper edge, such that the two edges of the discoverlap on the angle segment which is between the lines 88 and 91.

This embodiment of the flap valve permits simple replacement of a wornor damaged flap valve, without having to dismantle the actual support.

FIG. 7 is an exploded view of a variant embodiment of a piston, which isdistinguished from the previous pistons by the specific form of the flapvalve and the method of attachment of the latter.

All the parts which are identical to those of the preceding embodimentshave the same reference numerals.

This piston variant is distinguished by the form of the flap valve whichconsists of four segments 92, 93, 94, 95. The segment 92 is shownseparately from the other segments, which are shown in the assembledposition. These segments can have the same shapes and the samedimensions, and can overlap in the manner of fish scales. As shown inthe variant in FIG. 7, it is also possible firstly to place two segments93 and 95 in a diametrically opposed position on the support 81-86, thento place the two segments 92 and 94 above the segments 93 and 95, thuscreating slight overlapping which is represented by the broken lines. Inthe case of a flap valve of this type, when the piston descends into thewater, the upper segments 92 and 94 are raised before the segments 93and 95. The segments 92 cover the upper 1/4 disc angle such as to beable to overlap as shown.

These segments are also extended by two curved lugs or hooks 96, 97 atthe aperture. These two lugs 96, 97 have a slit 98 between them.

The lugs 96, 97 and the slit 98 make it possible to place each segment,for example segment 92, such that it straddles a radial branch 82, andis disposed between the inner ring 83 and the directly adjacentintermediate ring 86. In the example shown, the first intermediate ringis very close to the upper hub 83, and the distance between these tworings leaves space for the lugs 96, 97.

When the segments of the flap valve 92-95 are thus positioned on thesupport which is previously attached to the rod 7 (not shown), the upperattachment unit is installed, consisting of two halves 99A, 99B whicheach end in assembly lugs 100, 101. These two parts 99A, 99B have athreaded inner surface, such that the two parts are joined to constitutea single continuous thread. These parts are assembled for example byscrews not shown, as indicated by the broken lines 104.

At their base, the parts 99A, 99B are extended by a half-flange 105,106; when the part is assembled the latter are complemented in order toform a flange which supports the segments 92-95 against the support ofthe piston 8 which has previously been put into place on the rod.

In fact after the segments 92-95 have been put into place, the two parts99A, 99B of the upper attachment unit 99 are assembled on the threadedpart 73 (FIGS. 2 and 3) of the rod 71, 7, then this unit 99A, 99B isscrewed in order to clamp the segments 92-95.

In order to ensure that this nut is locked such that it is not unscrewedby the effect of vibrations, the two parts 99A, 99B can be clampedagainst one another, if there is still a given amount of play betweenthem, in order to lock the threads of the surfaces 102, 103 in thethread of the threaded part 71, and to prevent unscrewing.

According to a variant which is not shown, the flap valve is in theshape of a tulip which is attached close to the outer edge of the outerring 81; the flap valve then opens around the rod which is optionallyprovided with a seal to form a seat for the edge of the flap valve. Inthis variant, the edges of the "petals" of the flap valve on the openingside can be joined by a ring which is engaged on the rod.

According to another variant, the flap valve in the shape of a tulipconsists of a single diaphragm with a frusto-conical shape which isattached by its outer edge, the inner edge which borders the apertureoptionally being provided with a ring which surrounds the rod; thisdiaphragm can also be provided with a part which forms the shutting seatagainst which the edge of the aperture of the flap valve is supported.

FIGS. 8 to 10 show another embodiment of a piston support according tothe invention. This support consists of two parts 200,201, which forexample are absolutely identical, i.e. which correspond substantially tothe support in FIG. 1, which is intersected by a diametral plane (whichpasses through the axis of the rod). These two halves are thus producedfrom a single mold. These two parts 200, 201 are assembled on the rod 7by assembly of a collar type. For this purpose, in the upper area and inthe lower area of each part, lugs complete the parts in order to formcollars.

In greater detail, according to FIG. 8, the left part 200 consists of anouter ring 81A which is connected by radii 82A to a hub 83A or innerring. In fact in the case of both the ring 81A and the ring 83A,half-rings are involved. The same applies to the intermediate half-rings86A.

The "right" part 201 comprises the same components as the "left" part200, with the same references in which the suffix A is replaced by thesuffix B.

The half-ring 83A is also longer than the thickness of the radii 82A orof the outer ring 81A, such that the lugs 108A, 109A are accessible forassembly of the two parts 200, 201.

The lower hub 84A also corresponds to a half-hub which is extended onboth sides by lugs 110A, 111A which are designed to be assembled, againin the manner of a ring, with the similar lugs 110B, 111B of the lowerhub 84B of the other part 201 (FIG. 10).

FIG. 10 also shows the initial parts of the branches 85A and 85B of thetwo parts 200, 201.

According to FIG. 9, the two parts 200, 201 are disposed on both sidesof the rod 7. It is sufficient to assemble them by means of the lugs ofthe upper collars (which incidentally are partially hidden by the radii82A, 82B).

The lower collars are also assembled.

This embodiment of the support provides the added advantage of simplerproduction, since the mold simply corresponds to half the shape of thesupport. Owing to the symmetry, the same mold can be used to produce theparts 200, 201.

This also considerably facilitates interventions on the pump installed,since it is necessary simply to unscrew and release the support alongthe rod 7, or to re-engage it along the axis of the rod 7, by means of aconnection between two rod components 71. A support can be attached inany position, by means of this assembly by collars. Fitting of the flapvalve is just as simple as in the case of the flap valve in FIG. 6. Thisflap valve is maintained against the upper part of the support by meansof an attachment part similar to a collar, which is not shown in thedrawings.

The perspective view in FIG. 11 shows the support which consists of twoparts 200, 201 which are similar to the support shown in FIG. 9. For thesake of simplification the legs 85A . . . are not shown in FIG. 11.

These legs are preferably disposed in planes other than the plane ofjoining of the two halves 200, 201.

On their lower part, along the joining plane, the two parts 200, 201comprises ribs 112A, 112B on which a clip 113, 114 is engaged. In somecases this method of assembly can be more advantageous for connection ofthe upper part of the support than a screw connection which is lessaccessible. On the other hand in their lower area, at the level of thelower hub, the parts 200, 201 can be connected by a screw connection oralso by a clip connection such as that which is described here. In thiscase the ribs can be parallel to the axis of the support, and can slidevertically. In order to prevent the clips from being detached by theeffect of vibrations, they can be locked by a small screw.

FIG. 12 shows a variant embodiment of the support, for example such asthat shown in FIG. 4. This support is completed on its periphery by askirt 115 which leaves a gap 116 relative to the wall of the raisingtube which is sufficient to prevent any friction, whilst neverthelesscreating a load loss area in order to slow down the flow of the waterwhich is being pumped. As clearly shown in FIG. 12, this skirt 115 isdisposed beneath the support, and not on the side of the flap valve 87.

Another embodiment of a piston according to the invention is describedhereinafter by means of FIGS. 13A-15B, 16, which show different variantembodiments of the support and the piston assembly.

According to FIG. 13A, the support 300 consists of a tubular hub 384,which combines the upper hub and the auxiliary hub of the precedingembodiments.

The legs 385 are constituted by fins with a triangular shape, a firstside 385a of which is attached to the hub 384, and a second 385b side ofwhich constitutes a radius 382 which forms a support surface for theflap valve, which is not shown.

Although the different variants of the support comprise four legsconsisting of triangular fins, this number can be different, for examplethree or five, although an even number is preferable for productionbecause of the plane symmetry which it provides for the support.

The variant in FIG. 13B corresponds to the form of support in FIG. 13A,except that it is in two symmetrical halves according to a plane whichpasses through the axis of the rod. These two halves 301', 302' of thesupport 300' are assembled by their fins which are providedschematically with connection apertures 386'.

The support variant 400 according to FIG. 14A and its embodiment in twosymmetrical parts 400' in FIG. 14B correspond substantially to FIGS.13A, 13B, except that the radial side of the fins 382 is replaced by asurface 482 which is broader than the thickness of the fins.

In the case of FIG. 14B, for the surfaces which are intersected by theplane of symmetry, the support surfaces 482' are reduced by half, andcorrespond to the surfaces 482'A.

The variant support 500 in FIG. 15A and its embodiment 500' in twosymmetrical halves according to FIG. 15B are distinguished from theprevious variants by fins 585, 585' which have a thickness which isvariable from top to bottom. On the upper part, the fins 585, 585' forma relatively broad support surface, with dimensions which are identicalalong the entire length. This thickness is reduced towards the base.

In the case of the support 500' in two parts, the fins 585' which areintersected by the plane of symmetry have an overall thickness which isreduced by half.

In the different variants in FIGS. 14A-15B, the description of the partswhich are common to those of FIGS. 13A, 13B is not repeated.

According to FIG. 16, the piston consists of a support 600 which isconstituted by one of the supports of FIGS. 13A-15B and by flap valves610 which are in the form of disc segments made of a rigid material.

These flap valve segments 610 are articulated on one (611) of theirstraight sides on the support surface 682 of each fin 685, whereas theother straight side 612 rests freely on the support surface 682 of thefollowing fin (the reference numbers selected for the different parts ofthe flap valve are the same).

These parts 610 can be pivoted and can for example assume the raisedposition shown in FIG. 16, in order to descend in the fluid (water).

During the raising movement, the parts of the flap valve 610 are heldagainst the support surfaces 682 of the support.

The movement of raising the parts 610 can be carried out virtually tothe vertical position, without going beyond this position, such that thethrust of the water during raising of the piston always holds down eachpart of the flap valve on the same side.

The direction of opening the parts 610 is preferably the same for allthe parts of a single piston. However this direction can be invertedfrom one piston to another in order to prevention induction of torque inrod 7.

The type of piston according to FIG. 16 is particularly advantageous fordescent to great depths, in order to resist efficiently substantialheights of water column.

What is claimed is:
 1. A vertical reciprocating pump for raising fluids from a fluid table, comprising:a pump outlet; a raising tube interconnecting said pump outlet and the fluid table, said raising tube having two ends; a base valve on one said end of said raising tube; a reciprocable rod supporting a piston, said piston comprising:an upper hub and a lower hub, said lower hub located below said upper hub, an outer ring connected by a plurality of branch members to said upper hub, said upper and lower hubs each connected for reciprocating movement with said rod, said outer ring connected to said lower hub by a plurality of angled leg members, said piston and said raising tube contacting one another at a plurality of points of contact, said points of contact disposed substantially in a plane; a control connected to said rod for controlling reciprocating movement of said rod; anda piston valve disposed above said outer ring, said branch members and said upper hub.
 2. The pump according to claim 1, wherein said valve comprises a diaphragm having an outer edge and an aperture, said aperture being sized to accommodate said rod, said diaphragm being cut between said outer edge and said aperture.
 3. The pump according to claim 1, wherein said branch members extend radially from said upper hub to said outer ring.
 4. The pump according to claim 1, further comprising:a plurality of lugs affixed to said upper hub and a plurality of lugs affixed to said lower hub.
 5. The pump according to claim 1, wherein said diaphragm comprises a split disc.
 6. The pump according to claim 1, wherein said valve comprises a disc shaped diaphragm.
 7. The pump according to claim 1, wherein said piston is formed from two, and in particular symmetrical parts, assembled to one another with said rod held there between.
 8. A vertical reciprocating pump, comprising:a pump outlet; a raising tube interconnecting said pump outlet and a fluid table, said raising tube having two ends; a base valve on one said end of said raising tube; a reciprocable rod supporting a piston; a control connected to said rod for controlling reciprocating movement of said rod; wherein said piston comprises:a hub connected for reciprocating movement with said rod; a plurality of triangular legs, a first side of each of said legs affixed to said hub; and a valve supported by a second side of each of said legs.
 9. The pump according to claim 8, wherein a plurality of radial surfaces are affixed to said hub and to said second sides of said legs.
 10. The pump according to claim 8, wherein said valve is formed from a plurality of valve segments, each of said valve segments connected to one of said second sides of said legs.
 11. A vertical reciprocating pump for raising fluids which are present in the ground, comprising:a pump outlet; a raising tube interconnecting said pump outlet and a fluid table, said raising tube having two ends; a base valve on one said end of said raising tube; a reciprocable rod supporting a piston; a control connected to said rod for controlling reciprocating movement of said rod; wherein said piston comprises:an outer ring connected by a plurality of branch members to an upper hub, said upper hub connected for reciprocating movement with said rod, wherein all points of contact between said piston and said raising tube lie substantially in a plane; and an intermediate ring connected to said branch members; a valve disposed above said outer ring, said branch members and said upper hub, wherein said valve comprises a disc shaped diaphragm, and wherein said diaphragm comprises a plurality of overlapping segments having curved lugs sized to fit between said hub and said intermediate ring; and an upper attachment unit locking said segments against said piston. 